<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        #app {
            display: flex;
        }
    </style>
</head>

<body>
    <!-- 准备一个使用样式的 DOM 容器 -->
    <!-- <div id="app">
        <div class="box2">less</div>
        <div class="box3">sacc/scss</div>
        <div class="box4"></div>
        <div class="box5"></div>
    </div> -->

    <div id="test"></div>
    
</body>

</html>